GE EV-1 DC motor controller

The EV-1 SCR (silicon controlled resistance) type of controller actually has decent features: including adjustable acceleration (via a potentiometer), automatic motor field weakening (for faster motor speed under light load), and a "wide open" power bypass that effectively connects the batteries directly to the motor when high current is demanded. (Think: turbo!)

It's a reliable controller that was fairly widely used in industry and in some earlier EV conversions.

But it's old technology, and one thing I learned from the EVDL is that it isn't ideal for use with a small battery pack (relative to forklift packs weighing several thousand pounds). The explanation is a little over my head, but has to do with the fact that the EV-1 lacks the capa citors that a more modern PWM style controller has. Lacking capacitance, current drawn via the EV-1 tends to be harder on a small pack, leading to lower efficiency (somewhat reduced range and battery life).